Hybrid motor vehicles utilize a propulsion system which incorporates both an internal combustion engine and an electrical system which is used typically for propulsion and regenerative braking. The electrical system includes at least one electrical motor mechanically connected to one or more axles of the motor vehicle and a battery pack of cells which is an integrated component of an energy storage system (ESS) that is electrically connected to the at least one motor. When the at least one motor propels the motor vehicle, electrical energy is extracted from the ESS (the battery pack discharges). During regenerative braking the motor acts as a generator, and the electrical energy generated is delivered to the ESS (the battery pack charges).
FIGS. 1 and 2 schematically depict aspects of a conventional hybrid ESS and the prior art thermal conditioning arrangement therefor.
Within the passenger cabin 10 of the hybrid motor vehicle is disposed the ESS 12, which may, for example, rest on the vehicle floor 14 above the fore-aft floor “tunnel” 16. The ESS 12 is thermally conditioned by the movement of cabin air AC via an ESS blower 18, whereby the cabin air is circulated through the ESS, originating at least one permanently open entry vent 20 and exiting at least one permanently open exit vent 22, both vents being permanently open in the sense of being in permanently and completely open fluidic communication with the passenger cabin. The prior art has sometimes placed the entry vent near the output of the HVAC ducting, whereby cabin air AC and HVAC air AH can comingle before unselectively entering the entry vent. Operation of the ESS blower 18 is controlled by a hybrid vehicle integration control module (VICM) 24, utilizing temperature data from (among others) an inlet duct sensor 26a, an outlet duct sensor 26b, and an ESS temperature sensor 26c. The VICM 24 is connected to inputs and outputs by various data lines (see for example dashed lines in FIG. 2). These components are subject to an on-board diagnostics (OBD) requirement, whereby a signal is provided to the driver if a fault is detected in any of the components.
The passenger cabin includes a heating, ventilation and air conditioning (HVAC) module 28, which typically includes passenger input instruments 30 and an HVAC controller 32 which operates the HVAC module in response to the passenger input. Typically, the HVAC module includes an HVAC blower 34, an evaporator 36 for cooling the HVAC air to the cabin and a heater core 38 for heating the HVAC air to the cabin via HVAC ducting 40. These components are not subject to an OBD requirement.
Utilizing the cabin environment in the prior art to provide air for thermal conditioning of the ESS is effective only when the cabin air is not too hot nor too cold. For example, after a soak in hot sun or frigid cold, the ESS will be similarly either hot or cold, and the cabin air used to thermally condition the ESS will also be likewise hot or cold. This has problematic implications for the electrical charge/discharge performance of the ESS, which is temperature dependent. As discussed hereinbelow with respect to FIG. 3, there is an optimal ESS performance temperature range, and the cabin air temperature extremes can easily be outside (both above and below) this range.
And, this problem of administering ESS thermal conditioning in the prior art is not “solved” by merely placing the entry vent someplace near the outlet of the HVAC ducting, as the commingling of cabin air with HVAC air is haphazard, unselectable and takes too much time.
Accordingly, what remains needed in the art is a thermal conditioning system of hybrid vehicle ESS which does more than simply utilize cabin air therefor.